Hair or fur shed from pet cats, dogs, and other mammals can be particularly difficult to remove from clothing and other fabric articles during the laundering process because of its tendency to remain adherent to the fibers of the fabric, even after the washing and drying cycle has been completed. This problem can extend to lint and other fine material that can cling to fabric and resist dislodgement during normal washing and drying, whether using household appliances or commercial laundering equipment. The primary recourse has remained the use of brushes, mitts, adhesive rollers, and similar devices to manually remove pet hair and other adherent matter before or after laundering.
The majority of fur-bearing mammalian species have coats comprising multiple types of hairs having different properties that fulfill a particular function. For example, the down or secondary hairs are what form the undercoat of cats, keeping the animal warm, and typically comprise about 75% of the coat in most breeds. These hairs are short, fine, and generally kinked or wavy, properties that make them adherent to fabric surfaces. The next most common type, the awn hairs, protect the down hairs and are intermediate-sized with a rough cuticle surface that facilitate attachment to clothing fibers. The remaining hairs are the guard hairs, which comprise the visible topcoat of the animal. The cuticles of these hairs include microscopic barbs that make them particularly adherent to clothing. The type of coat found on a dog depends on the breed, but it typically comprises a topcoat of guard hairs that protect an undercoat of fine secondary or down hairs. Other than most primate and ungulate species (which typically lack the fine down hair undercoat), the majority of other mammalian species have at least both guard hairs and the secondary down hairs, these being similarly problematic when coming in contact with clothing or other fabric articles being laundered.
The problem of adherent animal hair and other fine matter is compounded during the drying phase of the laundering process because the environment is conducive for the buildup of static electricity, especially as the moisture from the laundered clothing is removed. In a tumble-type dryer, clothing articles make continual contact with the drum of the dryer and the surfaces of other articles. The resulting friction contributes to a buildup of electrostatic charge on the fabric article surfaces. This phenomenon is known as the triboelectric effect, which is a type of contact electrification in which certain materials become electrically charged after coming into contact with another different material and are then separated. The polarity and strength of the charges produced differ according to the materials, surface roughness, temperature, strain, and other properties. Thus, it is difficult to predict how a material will behave and only broad generalizations can be made. Many fabrics, especially wools and synthetics, have an inherent propensity to acquire either a positive or negative charge by losing or absorbing electrons, respectively. The electron (or proton) affinity of a particular material (its tendency to become positively or negatively charged) determines its position on the Triboelectric Series continuum. It is known that certain natural fibers, such as wool, typically acquire a positive charge, while polyester and most other synthetics fabrics tend to acquire a negative charge during frictional contact with another surface (nylon being an exception). Polytetrafluoroethyene (PTFE) and silicone rubber are materials having one of the strongest tendencies to acquire electrons and become negatively charged. Cotton fabric does not readily acquire either a positive or negative charge, but may either shed or acquire electrons during the drying phase. Fur and hair tends has a tendency to acquire a positive charge and may be drawn to negatively charged fabric surfaces, such as polyester, making them even more likely to adhere to the clothing. In particular, rabbit fur particularly is located well toward the positive charge end of the Triboelectric Series and is often used to generate static electricity (often by rubbing it on silk). Like most materials, however, hair or fur can become either positive or negative charged, depending on the environment and circumstances to which they are subjected.
Another factor complicating the removal of adherent matter is that during the drying cycle, clothing and other fabric articles typically become positively or negatively charged and become attractive to other oppositely charged articles. This causes the well-known phenomenon of static cling, which can trap hair-covered surfaces and other matter between articles, further adding to the problem by limiting the exposed surfaces from which hair, lint, etc, may dislodge. Chemical agents introduced during the drying cycle to reduce static cling have not provided a satisfactory solution to the problem of dislodging or removing hair clinging to fabric. Tennis balls and certain devices designed for use in the dryer, such as the commercially available Dryer Max™ Dryer Ball (a polymeric ball with a series of projections adapted to engage fabric), also have been reported to help separate clothing articles and reduce static cling within the dryer. Yet, these devices have generally proven largely inadequate in helping to dislodge pet hair and certain other foreign material on fabric surfaces, indicating that static alone is not the main culprit in the problem of lifting away animal hair. Adhesive-covered articles have been proposed as a laundering aids to lift and transfer hair from the fabric surfaces during the drying phase, but there are obvious limitations with this approach. The high moisture present in the initial phases of the drying cycle can rapidly degrade the effectiveness of the adhesive. This, along with the gradual accumulation of transferred matter, can render the adhesive insufficiently tacky to effectively pull hair from the fibers of the fabric and transfer it to the adhesive surface. Electrostatic attraction has been utilized in pet brushes as an additional means of lifting away hair, but static electricity alone is generally ineffective to dislodge adherent hairs from most fabric articles within the dryer environment.
What is needed is a laundering aid that can be effective within the environment of a tumble-type clothes dryer in reducing static cling while lifting away pet hair and other finer matter adhering to clothing and other fabric articles such that the amount of foreign matter remaining on the fabric surfaces would be greatly reduced when compared to standard drying practices.